In both interior and exterior carpentry, wood board and strips are frequently cut at various lengths and at various angles, including right angles. In the past, handsaws were generally used for such cuts but in more recent times, power saws of various sorts including table saws, radial arm saws, band saws, jigsaws, and portable circular power saws have been generally used in place of handsaws.
With handsaws, miter boxes were used for making controlled cuts, but such miter boxes are generally of no use with power saws.
With table saws that have a motor permanently fixed therein, the entire assembly can be adjusted by, for instance, turning the angle of an arm as in a radial saw to get the desired cut. This of course is entirely satisfactory, but requires that a separate tool be present on the job, which is usually a construction site, for such cuts.
Table saws and the like are often not available at construction sites, whereas circular power saws are virtually always available, but angled cuts have been generally difficult to make precisely with such saws since they are held by a person without any guiding arrangement.
Efforts have been made to provide a guide device for portable power saws.